Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Protection against Challenge.
Deletion of the African Swine Fever Virus Gene DP148R Does Not Reduce Virus Replication in Culture but Reduces Virus Virulence in Pigs and Induces High Levels of Protection against Challenge.
复制标题
DOI：
10.1128/jvi.01428-17
复制
发表时间：
2017-12-15
影响因子：
5.4
通讯作者：
Dixon LK
中科院分区：
文献类型：
--
作者：
Reis AL;Goatley LC;Jabbar T;Sanchez-Cordon PJ;Netherton CL;Chapman DAG;Dixon LK
非洲猪瘟病毒（ASFV）基因组编码的大约165种蛋白质中，许多与已知蛋白质没有显著相似性，也没有进行过实验研究。一种这样的蛋白质是DP 148 R。我们发现DP 148 R基因在感染后早期转录。该基因的缺失并没有减少病毒在巨噬细胞中的复制，表明它对这些细胞中的复制不是必需的。然而，从产生BeninΔ DP 148 R病毒的强毒株Benin 97/1中删除该基因，显著降低了病毒在体内的毒力。所有感染贝宁Δ DP 148 R病毒的猪均存活，仅在免疫后不久显示短暂的轻度临床体征。在用亲本强毒病毒攻毒后，通过肌内途径免疫的所有猪（11/11）和通过鼻内途径免疫的所有猪（5/6）均存活。攻毒后观察到轻度或无临床体征。正如预期的那样，对照非免疫猪出现了急性非洲猪瘟（ASF）的体征。在免疫后不久观察到病毒基因组和感染性病毒，与临床体征的发作一致（1006个基因组拷贝或50%组织培养感染剂量/ml）。病毒基因组水平在免疫后60天内持续下降。相比之下，感染性病毒在30至35天内不再可检测到。在免疫后第4 - 7天的血清中检测到γ干扰素（IFN-γ），在用全病毒刺激免疫淋巴细胞后分析的所有猪中均检测到IFN-γ产生细胞。ASFV特异性抗体从免疫后第10天开始检测。非洲猪瘟（ASF）是非洲、外高加索部分地区、俄罗斯联邦和几个欧洲国家的地方病。缺乏疫苗阻碍了控制。许多ASF病毒基因与已知基因缺乏相似性，尚未被鉴定。我们已经证明，其中之一，DP 148 R，在细胞中病毒复制的早期被转录，并且可以从病毒基因组中删除而不减少病毒复制。基因缺失的病毒BeninΔ DP 148 R在猪中引起轻度临床体征，并诱导高水平的保护以抵抗亲本强毒病毒的攻击。因此，该基因的缺失可以为疫苗的合理开发提供靶点。
Many of the approximately 165 proteins encoded by the African swine fever virus (ASFV) genome do not have significant similarity to known proteins and have not been studied experimentally. One such protein is DP148R. We showed that the DP148R gene is transcribed at early times postinfection. Deletion of this gene did not reduce virus replication in macrophages, showing that it is not essential for replication in these cells. However, deletion of this gene from a virulent isolate, Benin 97/1, producing the BeninΔDP148R virus, dramatically reduced the virulence of the virus in vivo. All pigs infected with the BeninΔDP148R virus survived infection, showing only transient mild clinical signs soon after immunization. Following challenge with the parental virulent virus, all pigs immunized by the intramuscular route (11/11) and all except one immunized by the intranasal route (5/6) survived. Mild or no clinical signs were observed after challenge. As expected, control nonimmune pigs developed signs of acute African swine fever (ASF). The virus genome and infectious virus were observed soon after immunization, coincident with the onset of clinical signs (∼106 genome copies or 50% tissue culture infective doses/ml). The levels of the virus genome declined over an extended period up to 60 days postimmunization. In contrast, infectious virus was no longer detectable by days 30 to 35. Gamma interferon (IFN-γ) was detected in serum between days 4 and 7 postimmunization, and IFN-γ-producing cells were detected in all pigs analyzed following stimulation of immune lymphocytes with whole virus. ASFV-specific antibodies were first detected from day 10 postimmunization. IMPORTANCE African swine fever (ASF) is endemic in Africa, parts of the Trans Caucasus, the Russian Federation, and several European countries. The lack of a vaccine hinders control. Many of the ASF virus genes lack similarity to known genes and have not been characterized. We have shown that one of these, DP148R, is transcribed early during virus replication in cells and can be deleted from the virus genome without reducing virus replication. The virus with the gene deletion, BeninΔDP148R, caused mild clinical signs in pigs and induced high levels of protection against challenge with the parental virulent virus. Therefore, deletion of this gene can provide a target for the rational development of vaccines.